Carbonyl Compounds + Carbohydrates and Lipids An aldohexose General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Carbonyl Group in Aldehydes and Ketones A carbonyl group, in an aldehyde, is attached to at least one H atom in a ketone, is attached to two carbon groups General, Organic, and Biological Chemistry

General, Organic, and Biological Chemistry Carboxylic Acids A carboxylic acid contains a carboxyl group, which is a carbonyl group (C═O) attached to a hydroxyl group (—OH) has the carboxyl group on carbon 1 General, Organic, and Biological Chemistry

General, Organic, and Biological Chemistry Esters In an ester, the H in the carboxyl group is replaced with an alkyl group O  CH3 — C—O—CH3 ester group General, Organic, and Biological Chemistry

Names of Some Typical Aldehydes General, Organic, and Biological Chemistry

Learning Check Classify each as an 1) aldehyde or 2) ketone. O O || || || || A. CH3—CH2—C—CH3 B. CH3—C—H CH3 O | || C. CH3—C—CH2—C—H D. | CH3 General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Learning Check Classify each as an 1) aldehyde, 2) ketone, 3) alcohol, or 4) ether. O ║ A. CH3─CH2─C─CH3 B. CH3─O─CH3 CH3 O OH │ ║ │ C. CH3─C─CH2─C─H D. CH3─CH─CH3 │ CH3 General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Guide to Naming Aldehydes, ketones and carboxylic acids Aldehyde and carboxylic acids both at ends of a carbon chain. General, Organic, and Biological Chemistry

Naming Aldehydes, Ketones and Carboxylic acids An aldehyde has an IUPAC name in which the e in the alkane name is changed to al O O O ║ ║ ║ H−C−H CH3−C−H CH3−CH2−C−H Methanal Ethanal Propanal A Ketone in the IUPAC system by replacing the e in the alkane name with one; the carbonyl carbon is indicated by a number O O ║ ║ CH3−C−CH3 CH3−C−CH2−CH3 Propanone 2-Butanone General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Example of Writing IUPAC Names for Carboxylic Acids To write the IUPAC names of a carboxylic acid STEP 1 Replace the e in the alkane name with oic acid. CH4 Methane HCOOH Methanoic acid CH3—CH3 Ethane CH3—COOH Ethanoic acid STEP 2 Locate and name substituents, counting from the carboxyl carbon as carbon 1 General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Learning Check Name each of the following: O ║ 1. CH3─CH2─CH2─CH2─C─H 2. Cl─CH2─CH2─C─H 3. CH3─CH2─C─CH3 General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Learning Check Draw the condensed structural formulas for each of the following: A. 4-Methylpentanal B. 2,3-Dichloropropanal 3-Methyl-2-butanone 3-Methylbutanoic acid General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Polar Carbonyl Group The polar carbonyl group of aldehydes, ketones and carboxylic acids provides dipole–dipole interactions + - + - C═O C═O does not have H on the oxygen atom, aldehydes and ketones cannot be hydrogen bond donors, only acceptors Carboxylic acids are strongly polar have two polar groups: hydroxyl (−OH) and carbonyl (C═O) Both Hydrogen bond donor and aceptor General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

General, Organic, and Biological Chemistry Carbonyl compounds have higher boiling points and more soluble than alkanes General, Organic, and Biological Chemistry

Aldehydes Can Be Oxidized to Carboxylic acids, Ketones Cannot Aldehydes are easily oxidized to carboxylic acids. O O || [O] || CH3—C—H CH3—C—OH Acetaldehyde Acetic acid [O] = Ag+ or Cu2+ General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Aldehydes and Ketones Can Undergo Addition Reactions When a polar molecule adds to the carbonyl group of an aldehyde or ketone, the negative part of the added molecule bonds to the positive carbonyl carbon the positive part of the added molecule bonds to the negative carbonyl oxygen General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

General, Organic, and Biological Chemistry Cyclic Hemiacetals In glucose, a cyclic hemiacetal between the C═O group and the —OH forms a stable, six-atom ring General, Organic, and Biological Chemistry

General, Organic, and Biological Chemistry Carbohydrates a major source of energy from our diet composed of the elements C, H and O also called saccharides, which means “sugars” are produced by photosynthesis in plants such as glucose are synthesized in plants from CO2, H2O, and energy from the sun are oxidized in living cells (respiration) to produce CO2, H2O, and energy General, Organic, and Biological Chemistry

Types of Carbohydrates The types of carbohydrates are monosaccharides, the simplest carbohydrates disaccharides, which consist of two monosaccharides polysaccharides, which contain many monosaccharides General, Organic, and Biological Chemistry

Monosaccharides 3 to 6 carbon atoms (typically) a carbonyl (C=O) group – aldehyde (aldose) or ketone (ketose) several hydroxyl groups (-OH) end in -ose may include the number of carbons in the molecule: triose (3 C atoms) tetrose (4 C atoms) pentose (5 C atoms) hexose (6 C atoms) General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Monosaccharides Aldoses vs Ketoses Aldoses have an aldehyde group Ketoses have a ketone group Carbonyl at C1 Carbonyl at C2 General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Examples of Monosaccharides General, Organic, and Biological Chemistry

Learning Check Identify each as aldo- or keto- and as tetrose, pentose or hexose. A. B. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Solution Identify each as aldo- or keto- and as tetrose, pentose or hexose: A. B. aldohexose ketopentose General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Fischer Projections a 2-dimensional representation of a molecule places the most oxidized group at the top uses vertical lines for bonds that go back uses horizontal lines for bonds that go forward L structures —OH on left (second to last carbon) D structures —OH on the right (second to last carbon) General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

D and L Notations L - General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Learning Check Identify each as the D or L isomer. A. B. C. __-Ribose __-Threose __-Fructose General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

D-Glucose, D-Fructose, D-Galactose an aldohexose with the formula C6H12O6 In fruits and honey blood sugar in the body glucose has a normal blood level of 70–90 mg/dL the monosaccharide in polymers of starch, cellulose, and glycogen D-Fructose is a ketohexose with the formula C6H12O6 Is converted to glucose in the body D-Galactose In the dissaccaride, lactose, milk sugar General, Organic, and Biological Chemistry

Haworth Structures are cyclic forms of monosaccharides of hexoses form when the second to last —OH on reacts with a C═O group Aldohexoses form 6 member rings Ketohexoses and aldopentoses form 5 member rings b-D-Ribose An aldohexose A ketohexose An aldopentose General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Important Disaccharides A disaccharide consists of two monosaccharides Monosaccharides Disaccharide Glucose + glucose maltose + H2O Glucose + galactose lactose + H2O Glucose + fructose sucrose + H2O General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Polysaccharides Known as complex carbohydrates are polymers of D-glucose include amylose and amylopectin, starches made of -D-glucose include glycogen (animal starch in muscle and liver), which is made of -D-glucose include cellulose (plants and wood), which is made of -D-glucose General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Lipids biomolecules that contain fatty acids or a steroid nucleus soluble in organic solvents but not in water named for the Greek word lipos, which means “fat” extracted from cells using organic solvents Triglycerides made of 3 fatty acids 32 32

Fatty Acids Fatty acids are long-chain carboxylic acids typically contain 12 to 18 carbon atoms are insoluble in water can be saturated or unsaturated 33 33

Fatty Acid Formulas The formulas for fatty acids are written as condensed structural formulas line-bond formulas 34 34

Saturated Fatty Acids Saturated fatty acids have single C—C bonds molecules that fit closely together in a regular pattern strong attractions between fatty acid chains high melting points that make them solids at room temperature General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Unsaturated Fatty Acids one or more double C═C bond typically contain cis double bonds “kinks” in the fatty acid chains fewer attractions between chains and do not pack closely lower melting points are liquids at room temperature Trans-fats made of these General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Structure and Polarity of a Glycerophospholipid Note the “kink” General, Organic, and Biological Chemistry

Cell Membranes Cell membranes consist of a lipid bilayer made of two rows of phospholipids have an inner portion made of the nonpolar tails of phospholipids with the polar heads at the outer and inner surfaces 38 38